Hydrangea plant named ‘H218924’

ABSTRACT

A new and distinct cultivar of Hydrangea plant named ‘H218924’, characterized by its upright and uniformly mounded plant habit; vigorous growth habit and rapid growth rate; freely branching habit with strong, thick and sturdy stems; freely and uniformly flowering habit; large lacecap-type inflorescences with numerous sterile flowers that are yellow green to white in color; and good postproduction longevity.

Botanical designation: Hydrangea macrophylla.

Cultivar denomination: ‘H218924’.

BACKGROUND OF THE INVENTION

The present invention relates to a new and distinct cultivar of Hydrangea plant, botanically known as Hydrangea macrophylla, commercially referred to as a lacecap-type Hydrangea and hereinafter referred to by the name ‘H218924’.

The new Hydrangea plant is a product of a planned breeding program conducted by the Inventor in De Kwakel, The Netherlands and Lengerich, Germany. The objective of the breeding program was to create new strong and freely-branching Hydrangea plants with strong sturdy stems, uniform flowering habit, large inflorescences with numerous showy sterile flowers, attractive sterile flower color and good postproduction longevity.

The new Hydrangea plant originated from a cross-pollination made by the Inventor in March, 2014 in De Kwakel, The Netherlands, of Hydrangea macrophylla ‘H212905’, disclosed in U.S. Plant Pat. No. 26,508, as the female, or seed, parent with Hydrangea macrophylla ‘Horklewi’, not patented, as the male, or pollen, parent. The new Hydrangea plant was discovered and selected by the Inventor as a single flowering plant from within the progeny of the stated cross-pollination in a controlled greenhouse environment in Lengerich, Germany in March, 2015.

Asexual reproduction of the new Hydrangea plant by vegetative tip cuttings in a controlled environment in De Kwakel, The Netherlands since April, 2015 has shown that the unique features of this new Hydrangea plant are stable and reproduced true to type in successive generations.

SUMMARY OF THE INVENTION

Plants of the new Hydrangea have not been observed under all possible combinations of environmental conditions and cultural practices. The phenotype may vary somewhat with variations in environmental conditions such as temperature and light intensity without, however, any variance in genotype.

The following traits have been repeatedly observed and are determined to be the unique characteristics of ‘H218924’. These characteristics in combination distinguish ‘H218924’ as a new and distinct Hydrangea plant:

-   -   1. Upright and uniformly mounded plant habit.     -   2. Vigorous growth habit and rapid growth rate.     -   3. Freely branching habit with strong, thick and sturdy stems.     -   4. Freely and uniformly flowering habit.     -   5. Large lacecap-type inflorescences with numerous sterile         flowers that are yellow green to white in color.     -   6. Good postproduction longevity.

Plants of the new Hydrangea can be compared to plants of the female parent, ‘H212905’. Plants of the new Hydrangea differ primarily from plants of ‘H212905’ in branching habit as plants of the new Hydrangea are more freely branching than plants of ‘H212905’.

Plants of the new Hydrangea can be compared to plants of the male parent, ‘Horklewi’. Plants of the new Hydrangea differ primarily from plants of ‘Horklewi’ in inflorescence type as plants of the new Hydrangea have lacecap-type inflorescences whereas plants of ‘Horklewi’ have mophead-type inflorescences.

Plants of the new Hydrangea can be compared to plants of the Hydrangea macrophylla ‘H211903’, disclosed in U.S. Plant Pat. No. 25,320. In side-by-side comparisons, plants of the new Hydrangea differ primarily from plants of ‘H211903’ in the following characteristics:

-   -   1. Plants of the new Hydrangea are more vigorous and broader         than plants of ‘H211903’.     -   2. Plants of the new Hydrangea have smaller leaves than plants         of ‘H211903’.     -   3. Plants of the new Hydrangea have broader panicles than plants         of ‘H211903’.     -   4. Panicles of plants of the new Hydrangea have more fertile and         sterile flowers than panicles of plants of ‘H211903’.     -   5. Sterile flowers of plants of the new Hydrangea are yellow         green to white in color whereas sterile flowers of plants of         ‘H211903’ are bright pink in color.

BRIEF DESCRIPTION OF THE PHOTOGRAPHS

The accompanying colored photographs illustrate the unique appearance of the new Hydrangea plant showing the colors as true as it is reasonably possible to obtain in colored reproductions of this type. Colors in the photographs may differ from the color values cited in the detailed botanical description which accurately describe the colors of the new Hydrangea plant.

The photograph on the first sheet is a side perspective view of a typical flowering plant of ‘H218924’.

The photograph on the second sheet is a close-up view of a typical inflorescence of ‘H218924’.

DETAILED BOTANICAL DESCRIPTION

Plants used in the aforementioned photographs and in the following description were grown during the late spring and early summer in 13-cm containers in a glass-covered greenhouse in De Kwakel, The Netherlands and under cultural practices typical of commercial Hydrangea production. During the production of the plants, day and night temperatures averaged 17° C. Plants of the new Hydrangea were one year old when the photographs and description were taken. Plants of the new Hydrangea are not treated with aluminum sulfate to “blue” the inflorescences. In the following description, color references are made to The Royal Horticultural Society Colour Chart, 2015 Edition, except where general terms of ordinary dictionary significance are used.

-   Botanical description: Hydrangea macrophylla ‘H218924’. -   Parentage:     -   -   Female, or seed, parent.—Hydrangea macrophylla ‘H212905’,             disclosed in U.S. Plant Pat. No. 26,508.         -   Male, or pollen, parent.—Hydrangea macrophylla ‘Horklewi’,             not patented. -   Propagation:     -   -   Type cutting.—By vegetative tip cuttings.         -   Time to initiate roots, summer.—About two weeks at             temperatures about 23° C.         -   Time to initiate roots, winter.—About 18 days at             temperatures about 20° C.         -   Time to produce a rooted young plant, summer.—About four             weeks at temperatures about 23° C.         -   Time to produce a rooted young plant, winter.—About five             weeks at temperatures about 20° C.         -   Root description.—Thick; typically whitish brown in color,             actual color of the roots is dependent on substrate             composition, water quality, fertilizer type and formulation,             substrate temperature and physiological age of roots.         -   Rooting habit.—Freely branching; dense. -   Plant description:     -   -   Plant and growth habit.—Upright and uniformly mounded plant             habit; strong and sturdy stems; rapid growth rate and             vigorous growth habit.         -   Plant height.—About 25 cm to 30 cm.         -   Plant diameter or area of spread.—About 60 cm. -   Lateral branch description:     -   -   Branching habit.—Freely branching habit; when pinched, about             eight lateral branches develop per plant.         -   Length.—About 25 cm.         -   Diameter.—About 6 mm.         -   Internode length.—About 5 cm to 7 cm.         -   Texture.—Smooth, glabrous; fully developed, woody.         -   Aspect.—Upright to about 20° from vertical.         -   Strength.—Strong, sturdy.         -   Color.—When developing: Close to 144B; at internodes, close             to 187A; lenticels, close to 187A. Developed: Close to 144B;             at the internodes, close to 187A; when woody, close to 177C;             lenticels, close to 187A. -   Leaf description:     -   -   Arrangement.—Opposite, simple.         -   Length.—About 7 cm to 10 cm.         -   Width.—About 6 cm to 7 cm.         -   Shape.—Ovate.         -   Apex.—Acute to cuspidate.         -   Base.—Obtuse.         -   Margin.—Dentate to serrate.         -   Texture, upper surface.—Smooth, glabrous.         -   Texture, lower surface.—Rugose, glabrous.         -   Venation pattern.—Pinnate.         -   Color.—Developing and fully expanded leaves, upper surface:             Close to 139A; venation, close to 145B. Developing and fully             expanded leaves, lower surface: Close to 137D; venation,             close to 146D.         -   Petioles.—Length: About 2 cm to 3 cm. Diameter: About 4 mm.             Texture, upper and lower surfaces: Smooth, glabrous. Color,             upper surface: Close to 145B. Color, lower surface: Close to             145C. -   Flower description:     -   -   Flower type and habit.—Showy sterile flowers and smaller             fertile flowers arranged on lacecap-type terminal panicles;             panicles flattened globular in shape; flowers face upright             to outwardly depending on their position in the             inflorescence.         -   Fragrance.—None detected.         -   Natural flowering season.—Plants begin flowering about 9 to             14 months after planting; flowering begins in the early             summer and is continuous throughout the summer in Northern             Europe.         -   Flower longevity.—Fertile flowers last about one month on             the plant, fertile flowers not persistent; sterile flowers             last about three months on the plant, sterile flowers             persistent.         -   Quantity of flowers.—Freely flowering habit; about 120 to             150 fertile flowers per panicle and about 30 to 40 sterile             flowers per panicle.         -   Panicle height.—About 7 cm to 9 cm.         -   Panicle diameter.—About 20 cm to 25 cm.         -   Fertile flower buds.—Length: About 3 mm. Diameter: About             3 mm. Shape: Spherical. Color: Close to 155A.         -   Sterile flower buds.—Length: About 3 mm. Diameter: About             3 mm. Shape: Spherical. Color: Close to 155A.         -   Fertile flower diameter.—About 3 mm.         -   Fertile flower depth (height).—About 3 mm.         -   Sterile flower diameter.—About 5 cm to 6 cm.         -   Sterile flower depth (height).—About 1 cm.         -   Petals, fertile flowers.—Quantity and arrangement: Four in a             single whorl. Length: About 3 mm. Width: About 2 mm. Shape:             Ovate. Apex: Acute. Base: Obtuse. Margin: Entire. Texture,             upper and lower surfaces: Smooth, glabrous. Color: When             opening, upper and lower surfaces: Close to 155A. Fully             opened, upper and lower surfaces: Close to 155A; color does             not change with development.         -   Petals, sterile flowers.—Quantity and arrangement: Four in a             single whorl. Length: About 3 mm. Width: About 2 mm. Shape:             Ovate. Apex: Acute. Base: Obtuse. Margin: Entire. Texture,             upper and lower surfaces: Smooth, glabrous. Color: When             opening, upper surface: Close to NN155D. When opening, lower             surface: Close to 157D. Fully opened, upper and lower             surfaces: Close to NN155D; color does not change with             development.         -   Sepals, fertile flowers.—Quantity and arrangement: Five in a             single whorl. Length: About 1.5 mm. Width: About 1.5 mm.             Shape: Ovate. Apex: Acute. Base: Obtuse. Margin: Entire.             Texture, upper and lower surfaces: Smooth, glabrous. Color:             When opening, upper and lower surfaces: Close to 155A. Fully             opened, upper and lower surfaces: Close to 155A; color does             not change with development.         -   Sepals, sterile flowers.—Quantity and arrangement: Four in a             single whorl. Length: About 2.5 cm. Width: About 2.5 cm to             3.5 cm. Shape: Deltoid. Apex: Obtuse. Base: Cuneate. Margin:             Slightly dentate. Texture, upper surface: Smooth, glabrous.             Texture, lower surface: Rugose, glabrous. Color: When             opening, upper and lower surfaces: Close to 144D becoming             closer to NN155B with development. Fully opened, upper and             lower surfaces: Close to NN155B; with development, color             becoming closer to 144D with random sectors of close to             181B.         -   Pedicels, fertile flowers.—Length: About 1 cm. Diameter:             About 1 mm. Strength: Strong. Aspect: Mostly upright.             Texture: Smooth, glabrous. Color: Close to NN155A.         -   Pedicels, sterile flowers.—Length: About 3 cm to 3.5 cm.             Diameter: About 2 mm. Strength: Strong. Aspect: Erect to             about 45° from vertical. Texture: Smooth, glabrous. Color:             Close to NN155B.         -   Reproductive organs, fertile flowers.—Stamens: Quantity per             flower: Eight. Filament length: About 1 mm. Filament color:             Close to NN155D. Anther length: About 1 mm. Anther shape:             Conical. Anther color: Close to NN155B. Pollen amount:             Abundant. Pollen color: Close to 155D. Pistils: Pistil             quantity per flower: Three. Pistil length: About 3 mm.             Stigma shape: Oval. Stigma color: Close to NN155A. Style             length: About 2 mm. Style color: Close to NN155A. Ovary             color: Close to NN155A.         -   Reproductive organs, sterile flowers.—Stamens: Quantity per             flower: Three. Filament length: About 1 mm. Filament color:             Close to 155B. Anther length: About 1 mm. Anther shape:             Conical. Anther color: Close to 155B. Pollen amount: Scarce.             Pollen color: Close to 155D. Pistils: Pistil quantity per             flower: Three. Pistil length: About 3 mm. Stigma shape:             Oval. Stigma color: Close to 73B. Style length: About 2 mm.             Style color: Close to 65C. Ovary color: Close to 65C.         -   Seeds, only produced by fertile flowers.—Quantity per             fertile flower: About 20 to 30. Length: About 0.5 mm.             Diameter: About 0.1 mm. Color: Close to 200C. -   Pathogen & pest resistance: Under commercial production conditions,     plants of the new Hydrangea have not been observed to be resistant     to pathogens and pests common to Hydrangea plants to date. -   Temperature tolerance: Plants of the new Hydrangea have been shown     to be tolerant to temperatures ranging from about 3° C. to about 38°     C. 

It is claimed:
 1. A new and distinct Hydrangea plant named ‘H218924’ as illustrated and described. 